Seal for floating deck



March 12, 196 8 D 5 ETAL 3,372,831

SEAL FOR FLOATING DECK Filed April 13, 1965 l v! ms 5 ma M m m VA-U w k A Jr. we y Au Y B United States Patent 3,372,831 SEAL FOR FLOATING DECK Frank J. Daniels, Baldwin, N.Y., and Lou C. Creitli,

Allentown, Pa., assignors to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Apr. 13, 1965, Ser. No. 447,804 7 Claims. (Cl. 220-26) ABSTRACT OF THE DISCLOSURE This invention relates in general to an improvement in floatmg decks for use within a liquid storage tank, and more particularly to an improved seal for such floating decks.

Floating decks of many types and forms have been proposed and used in tanks designed for the storage of various liquids. Such a deck may form the roof for the storage tank, or may be an additional member within a tank having a fixed roof. In either case, the deck floats substantially horizontally on the surface of the liquid in the tank and moves upwardly and downwardly with the surface as the volume of liquid in the tank changes. Thus, protection is afforded from the elements and prevents evaporation of the liquids stored in the tank.

The conventional floating deck is of a smaller radial dimension than the tank in which it is installed, in order to provide a clearance space between the periphery of the floating deck and the shell of the tank for accommodating local dimensional variations in the tank shell, known as out-ofroundness in the case of cylindrical tanks, which results from irregularities in the interior surface of the tank shell. To prevent evaporation of the liquid below the floating deck, it is necessary that this clearance space be effectively sealed without impeding the motion of the floating deck as it changes position. Seals which have been previously proposed are of a complicated construction, difficult to install, and expensive to maintain.

According to the instant invention, it has been found that an inexpensive and yet highly effective seal can be obtained by securing to the peripheral edge of the floating deck a ring of an impermeable, flexible material which is of a width greater than the clearance space between the deck and the tank shell. Thus, the ring is flexed against the tank shell and forms an effective seal, and yet does not impede the motion of the floating deck.

Accordingly, a principal object of the instant invention is to provide a new and improved seal for use with a floating deck in a liquid storage tank.

Another object of this invention is to provide such a seal which is simple in construction and easy to install.

A still further object of this invention is to provide such a seal which will not impede the motion of the floating deck as it changes its position.

Other objects and advantages will become apparent to those skilled in the art as a detailed description of a particular embodiment proceeds with reference to the drawings which form a part hereof, and in which:

FIGURE 1 is a partial perspective sectional view of a floating deck disclosing the manner in which the novel seal of this invention is attached; and

FIGURE 2 is a cross-sectional view of the seal in position in contact with the interior surface of a tank shell.

Referring now to FIGURE 1 of the drawings, a portion of the seal of the instant invention is illustrated at 10. Seal 10 consists of two rings 11 and 12 extending about the peripheral edge of the floating deck. The rings 11 and 12 may be fabricated from any suitable resilient material which is impervious and impermeable to the liquid stored, for example natural rubber. Obviously, where the seal is to be used on a deck which serves as the roof of the tank, the material of the rings must also be of a material resistant to the type of weather encountered.

Most liquid storage tanks being of a circular crosssectional configuration, the rings 11 and 12 are of an annular configuration, the inner edges being aifixed to the floating deck, and the outer edges extending toward the tank shell. The rings 11 and 12 may be attached to the floating deck in any suitable manner, but are shown as being attached to a peripheral edge portion 13. To insure a sealing engagement between the rings 11 and 12 and the portion of the floating deck to which it is attached, there may be oriented completely around the upper periphery of one of the sheets 11 a plurality of straps 14, shown here as being channel members. Such strap members serve to force the seal 10 into tight engagement with the portion of the floating deck to which it is attached throughout its engaging periphery. As can be seen in FIG- URE 1, the straps 14 are of a short, straight length of channel, with joining strips 15 between adjacent strips 14. This arrangement has been found to be an inexpensive one and adapted to any size of seal. However, it will be obvious that other arrangements are possible, for example, a single, continuous strap member may be sized to fit a particular seal.

In FIGURE 2 there is seen the seal of the instant invention in use. A floating deck 16 of any of the known types is shown within a liquid storage tank having a tank shell 17 and containing a liquid 18. The seal 10 is at tached to the peripheral edge portion 13; it will be evident that the straps 14 and connecting strips 15 are secured to the peripheral portion 13 as by a plurality of bolts 21 and nuts 22.

As can be seen in FIGURE 2, one of the rings, 12, is of a width less than the distance between the peripheral edge 13 of the floating deck 16 and the tank shell 17. The other ring 11 is of a width greater than this distance, and accordingly, in use, the seal must flex upwardly or downwardly in engagement with the tank shell 17, thus assuring an effective seal. It will be evident that as the floating deck 16 moves upwardly, the seal Ill will assume the position shown in FIGURE 2, and that as the floating deck 16 moves downwardly, the seal 10 will assume a position flexed in an opposite direction.

The ring 12 serves to rigidify the portion of ring 11 not in contact with the tank shell 17. It will be obvious that any desired number of such additional rings may be employed, and that one or more may be of a thickness greater than the thickness of the ring 11.

The installation of the instant seal is as follows. The seal rings 11 and 12 may be fabricated from sheets of suitable thickness material by cutting a series of arcs having the desired radius of curvature, and joining the ends together to form continuous rings. As the ring 12 serves only a reinforcing function, this ring need not be continuous but may comprise a series of separate arcuate strips. A series of holes may then be punched around the inner edge to accommodate the bolts used in securing the seal to the peripheral edge of the floating deck. The ring 12 may first be set in place on the peripheral edge of the floating deck. If the bolts have been placed in position previously, the ring or ring segments may be merely dropped over the bolts. The upper ring 11 may then be fed into the storage tank through the manhole and installed in the same manner atop the ring 12. If the storage tank is devoid of interior poles, the ring 11-and, if it is continuous, the ring 12 also-may be inserted into the tank with their ends joined. Where poles are encountered, the rings may be installed before their ends are joined,

3 and the ends secured together in position about the peripheral edge of the floating deck. In any event, when both rings are in place, they are secured by clamping in place the straps and joining sections.

It will be apparent that the instant invention provides a seal which may be employed in a tank of any desired size and any desired configuration. Compound bending of the seal is avoided, and accordingly a longer life of the seal is obtained.

It is to be understood that the invention is not limited to the illustrations described and shown herein which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modifications of form, size, arrangement of parts and detail of operation, but rather is intended to encompass all such modifications which are within the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. A seal for use in a liquid storage tank having a tank shell and a floating deck provided with a peripheral edge spaced radially inwardly from said tank shell, comprising (A) a first substantially float ring of an impermeable,

flexible material secured at only its inner edge to said deck peripheral edge and extending radially outwardly therefrom toward said tank shell but terminating inwardly from said tank shell; and

(B) a second substantially float ring of an impermeable, flexible material superposed upon said first ring,

said second ring being secured at its inner edge only to said deck peripheral edge and extending radially outward therefrom toward said tank shell and sealingly engaging said tank shell.

2. A seal as defined in claim 1 wherein said second ring is continuous about the periphery of said peripheral edge.

3. A seal as defined in claim 1 wherein said first ring is of a thickness greater than said second ring.

4. A seal as defined in claim 1 wherein said second ring is of a width greater than the space between said tank shell and said deck peripheral edge, whereby said second ring is flexed upwardly or downwardly in engaging said tank shell.

5. In combination,

(A) a tank for the storage of liquids, said tank having an upstanding tank shell;

(B) a floating deck within said tank having a peripheral edge spaced radially inwardly from said tank shell leaving an annular space between said deck and said tank shell;

(C) a seal positioned in said annular space, comprising (1) a first substantially float annular ring of impermeable, flexible material, the width of said first annular ring being smaller than the width of said annular space,

(2) a second substantially float annular ring of impermeable, flexible material, the width of said second annular ring being greater than the width of said annular space;

(3) said first and second annular rings being in superposed relationship and secured to said deck peripheral edge at only their inner edges;

(D) means for securing said seal to said peripheral edge.

6. The combination of claim 5, wherein said means for securing said seal to said deck peripheral edge comprises:

(A) strap members superposed on said seal completely about the inner periphery thereof,

(B) a plurality of securing members at spaced intervals about the inner periphery of said seal securing said strap members and said superposed first and second annular rings to said deck peripheral edge.

7. The combination of claim 6 wherein said second annular ring is continuous.

References Cited UNITED STATES PATENTS 1,529,767 3/1925 Briers et al 22026 2,914,212 11/1959 Fino 220--26 3,049,261 8/1962 Wade et a1. 220-26 FOREIGN PATENTS 589,893 12/1933 Germany. 152,198 1962 U.S.S.R.

THERON E. CONDON, Primazy Examiner.

JAMES R. GARRETT, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,312,831 Dated March 12, 1968 Inv n d Ergnk ,1, mniels and Lou Q. Creith It is certified that error appears in the above-identified patent and that said Letters Patent ere hereby corrected u shown below:

In Column 3, line 23, the word "float" should read "flat";

In Column 3, line 28, the word "float" should read --f1at--.

In Co1umn 4, line 8, the word "float" should read "flat";

In Column 4, line 12, the word "float" should read "flat".

SIGNEQ AN D SEALED swam 

